Sonic mixing apparatus and method



March 19, 1963 E, LINDsEY 3,081,979

SONIC MIXING APPARATUS AND ME HOD Filed Nov. 20, 1959 -2 Sheets-Sheet 1v Fra. 4.' H62 1.

28 89 3 INVENTOR.

[EA/597' E. LINDSEY 5y HIS A 7'7'0/EMEKS Mae/s, K/Ech', Russsu. fiAfisavMarch 19, 1963 E. E. LINDSEY 3,081,979

some MIXING APPARATUS AND METHOD Filed Nov. 20, 1959 2 Sheets-Sheet 2Unite My invention relates to mixing devices and methods and moreparticularly to the intense mixing or homogenization of dissimilar fluidmaterials. It will be exemplified as applied to the making of toppingsor cream substitutes from vegetable oils although its uses are in nowiselimited thereto, the invention being capable of forming permanentemulsions or suspensions of a wide variety of materials.

It has been found that strong cavitation effects leading to intensemixing can be induced by jetting a gaseous medium against the free endof a vibratory member to set same into rapid vibration, usually in theultrasonic range, a stream of the material to be mixed being broughtinto the vicinity of the vibrating member. It is an object of theinvention thus to mix such a stream of material. Within the concepts ofthe invention such a stream should be a liquid stream but it can becomposed of one or more liquids with or without other gaseous or solidparticles dispersed therein. The terms liquid stream or stream of liquidmaterial are used to include such single or multiplephase systems.

In the preferred practice of the invention the gaseous medium used toset up the vibrations is one of the desired components of the ultimatemixture and is mixed with the material of the liquid stream as a resultof the vibrations it creates. It is an object of the invention thus toemploy the vibration-inducing gaseous medium as one component of theultimate mixture.

It is not essential that the gaseous medium remain in its same physicalor chemical state in the ultimate mixture. For example, it may beselected to react chemically with some component of the liquid stream.More commonly there may be some change in its physical state. Aparticularly advantageous operation is to employ steam as the gaseousmedium for inducing the vibrations and at the same time heating thematerial being mixed. If the liquid stream is of lower temperature thesteam will condense in situ in the material of the stream, formingminute droplets of water which may be very advantageous in the ultimateproduct. It is an object of the invention to induce vibrations in avibratory member by directing a steam jet thereagainst while deliveringa liquid stream to the zone of vibration, the steam and the liquidmixing in such zone, the steam condensing in situ to form minutedispersed droplets of water in the liquid and raising the temperature ofthe material being treated to such temperature as may be desired andadvantageous.

My earlier Patent No. 2,277,120 discloses prior equipment that has beenwidely used in the mixing or homogenization of various materials. Thematerials are recir culated in a closed path through a chamber'by use ofa high-pressure pump and a multi-oriiiced discharge head, the processbeing batch or semi-continuous. The present invention can be employed inconjunction with such prior equipment and can effect an intense mixingor homogenizing action on the recirculated materials to such extent thatthe mixing time can sometimes be decreased almost ten fold. In otherinstances the invention can be used by itself to exert an intense mixingaction on a liquid stream. In either instance the invention effects manyeconomies in equipment, space and time. It is an object of the inventionto induce such economies.

It is a further object of the invention to provide a StatesPatentquick-acting position-controlling means for controlling therelative positions of two nozzle members and thus controlling the flowof the gaseous medium therebetween.

Further objects reside in the combination of the aforesaid mixing deviceand auxiliary equipment by which the material to be mixed can berecirculated continuously through the vibratory zone. In this way it ispossible, for example, to build up the content of condensate to adesired value while still obtaining a more thoroughly mixed product.

Various other objects and advantages will be evident to those skilled inthe art from the following description of exemplary embodiments.

Referring to the drawings:

FIG. 1 is a pipe-line diagram showing the invention incorporated in anapparatus similar to that shown in my earlier Patent No. 2,277,120;

FIG. 2 is a sectional view of FIG. 1;

FIG. 3 is a sectional view taken along the line 3-3 of FIG. 2;

FIG. 4 is a fragmentary sectional view, similar to FIG. 2, showing analternative vibratory memben FIG. 5 is a view of the forward edge of thevibratory taken along the line 2--2 rnember taken as indicated by thearrow 5 of FIG. 4

and indicates diagrammatically one type of vibration that is possiblewith this type of vibratory member;

FIG. 6 is a view similar to FIG. 2 illustrating the elements inoperative position;

FIG. 7 is an exploded view of the elements of FIG. 2 with slightmodification; and

FIG. 8 is a sectional view of an alternative embodiment of theinvention.

Referring particularly to FIGS. 1-3, the mixing apparatus is indicatedgenerally by the numeral 15 and is shown as including a tubular housing18 threaded at opposite ends. The left-hand or entrance end of thetubular housing is closed by a massive ring 19 held in place by a Washer20 which is engaged by a flange 22 of a collar 23 threaded to thehousing. The right-hand end of the housing 18 as viewed in FIG. 2communicates with an exit conduit 25 carrying a beveled flange 26 whichis forced against a correspondingly beveled seat 27 of the housing by aflange 28 of a collar 29.

A nozzle 30 is disposed within the housing 18 and includes an outerannular member 31 dividing the interior of the housing 18 into an inletchamber 32 and a mixing chamber 33. The outer annular member 31 providesa neck 34 extending r-earwardly to be engaged by the forward face of themassive ring 19. By tightening the collar 23 a shoulder of the annularmember 31 is pressed against a shoulder 35 formed by a counterbore ofthe housing 18, forming a fluid tight fit.

Steam or other gaseous medium is supplied by a pipe 38 to the inletchamber 32 through a plurality of holes 36 drilled radially in the neck34. The zone outside the neck 34 acts as a manifold to distribute thesteam or gaseous medium uniformly around the periphery of the inletchamber 32.

The nozzle 30 includes also an inner annular member 38 cooperating withthe outer annular member 31 in defining a narrow annular orifice 4t)interconnecting the inlet chamber 32 and the mixing chamber 33 anddischarging a high-velocity annular stream into the mixing chamber in aforward direction substantially parallel to the axis of the housing 18.One of the annular members 31, 38 is made movable relative to the otherto control the discharge of the gaseous medium through the narrowannular orifice 40.- As shown, the outer annular member includes arearwardly facing conical surface 41 mating with a forwardly facingconical surface 42 of the inner annular member 38. These annular membersr'espectively have substantially cylindrical surfaces 43 and 44extending forwardly from the respective conical surfaces and providingtherebetween the narrow annular orifice 40 of this embodiment.

A suitable position-controlling means is employed to determine and fixthe relative positions of the annular members 31 and 38 of the nozzle.In FIGS. 1 and 2 this means includes a rod 45 secured to the innerannular member 33 and journalled by a sleeve 46 for longitudinalmovement in the direction of the axis of the housing 18. A suitablegland 47 seals the rod 45 in its to-and-fro movement. Such movement iscontrolled by an actuator shown as including a cylinder 50 in whichslides a piston 51 connected to the rod 45. The position of the pistonis determined by air or other fluid supplied to and exhausted fromopposite sides of the piston by use of a con ventional four-way valve54. When in the position shown, air is delivered to one side of thepiston and exhausted from the other to permit rearward movement. When inanother position the supply and exhaust of air will be reversed so thatthe piston will advance forwardly. In a third position the volumes ofair or other fluid on opposite sides of the piston will be entrapped tolock it in position. -In this way it is possible quickly to open, closeand adjust the nozzle 30 from a remote point and thus control accuratelythe gaseous medium issuing from the narrow annular orifice 40.

The high velocity annular jet of steam or other gaseous medium issuingfrom the narrow annular orifice 48 into the mixing chamber 33 isemployed to activate a vibratory means therein. This vibratory meanscomprises generally a base member 58 at a position downstream from theorifice 40 and a tubular vibratory member 60 afiixed thereto. In theembodiment of FIGS. 2, 6 and 7 the base member 58 is supported by athreaded shank 61 extending through the central opening of a spider 62and clamped rigidly thereto by a locknut 63. The base member includes adiverging portion 64 terminating in a relatively massive sleeve 65. Thissleeve is machined to receive and provide a shoulder abutting one end ofthe tubular vibratory member 60.

In this embodiment of the invention the tubular vibratory member 60 isshown as a relatively thin-walled steel tube with its rear portionfitting over and positioned by the sleeve 65 of the base member 58 andits forward portion terminating in a forward edge 66 positioned in thepath of the high-velocity jet of gaseous medium from the narrow annularorifice 40. The arrangement is such that this high-velocity jet willrapidly vibrate the forward end of the member 60, usually at frequenciesin the ultrasonic range. In the embodiment under consideration, theforward portion of the member 60 provides several reed-like cylindricalsegments 67 because of a plurality of slots 68 spaced around theperiphery of the member 60 and extending from the forward edge 66 in adirection substantially parallel to the axis of the housing 18. freeperiod of vibration of each reed-like cylindrical segment 67 dependsupon a number of factors including the thickness and character of thematerial, the length of the segment (determined by the depth of theslots 68) and the width of the segment (determined by the spacing of theslots 68). It is within the contemplation of the invention or widelydivergent frequencies.

The vibratory member 60 is preferably mounted in such a way that thedistance between its forward edge 66 and the nozzle 30 is adjustable. Inthis respect the threaded shank 61 permits such adjustment as comparedwith the spider 62 which is locked in place by being pressed against ashoulder 69 of the housing 18 by tightening of the collar 29.

A liquid stream to be mixed is advanced past the forward portion of thevibratory member 60 as the latter is vibrated by the gaseous mediumissuing from the nozzle 30. This liquid stream may enter the mixingchamber 33 at various positions. As shown in FIGS. 1 and 2, the liquidstream enters sidewardly through a leg 71 of the housing 18 whichprovides a circular inlet passage 72. It is preferable that this inletpassage open on the mixing chamber 33 at a position near the forwardedge 66 of the vibratory member. To control the effective area of thisinlet passage 72 and its position relative to inlet passage 72, leavinga segment thereof open as sug gested in FIG. 2.

The liquid stream thus introduced spreads around the mixing chamber 33and is acted upon or disrupted by the intense cavitation effects of thevibration. The liquid stream can leave the mixing passage exclusivelythrough an annular space 77 within the housing 18 around the vibratorymember, passing into the exit conduit 25 through the openings of thespider 62. This condition is suggested in FIGS. 6 and 7 where theinterior of the vibratory member is completely closed by its supportingbase member 58. With such an arrangement the liquid inside the vibratorymember can be replaced only by fiow through the slots 68 or by fiowthrough the zone between the forward edge 66 and the nozzle 30. Thismode of operation has been used successfully. In other instances,however, it is desirable that some or all of the mixed product leave themixing chamber 33 from a zone inside the tubular vibratory member 60. InFIG. 2 holes 73 in the diverging portion 64 of the base member 53 permitsome of the mixed product to flow therethrough to the exit conduit 25from the interior of the tubular vibratory member 60 while otherportions of the mixed product flow along the annular space 77. In theembodiment of FIG. 8, to be described, all of the mixed product leavesfrom the interior of the vibratory member.

In certain instances it is possible to induce rapid vibration ofsegments of the forward end of a tubular vibratory member even if thesesegments are joined together. For example, it is sometimes possible toeliminate the slots 68 in the vibratory member 60 as suggested in FIGS.4 and 5. The forward edge 66 is here continuous at one instant while thedot-dash line 82 suggests a momentary deviation from circularity in ahorizontal plane at another instant. Such deviations are of course notlimited to vertical and horizontal planes but can take place inintermediate planes.

achieved but the latter appear to be more efiective in creating thecavltational mixing desired.

intense cavitational effect at the outer surface of the segment. At asucceeding time when the segment is moving outwardly there will beintense cavitational effects immediately inside the segment. Bothcavitational actions are intense and are believed to be important increating the desired mixing and disruption of the molecular structure ofthe product being treated.

The condensation of the steam in situ is also effective in creating anintense mixing action aiding that produced by cavitation. Thecondensation of each steam particle is extremely rapid, causing apercussive collapse inducing forces similar to those experienced inwater hammer phenomena as the surrounding liquid contracts against aliquid condensate particle that has resulted from the volumetriccollapse of a steam particle. A steam jet inducing the vibrations anddesired mixing of the invention will provide billions of dispersed steamparticles which experience volumetric changes of the order of 1700:1when condensing.

In instances where the mixed product is to be withdrawn exclusively fromthe interior of the vibratory member, the construction of FIG. 8 can beutilized. Here a base member 100 fits the interior of the housing 18toeliminatethe annular space 77 and the use of the sleeve 74 previouslydescribed. The base member 100 provides a flange which seats against theshoulder 69 previously described, being thus held in place by the collar29. A tubular vibratory member 110 provides a reinforcing bead 111 andis mounted in a counterbore 112 of the base member 100. In thisembodiment the tubular vibratory member 110 is relatively short, theslots 114 thereof extending almost to the point of support. Likewise thecircular inlet passage 72 here remains open. The mixed product advancesthrough a taperedpassage 116 to the exit conduit 25.

Another constructional difference suggested in FIG. 8 is in the shape ofthe outer and inner annular members 120 and 121 forming the nozzle 122.In this embodiment the conical and substantially cylindrical surfaces 42and 44 of the inner member and 41 and 43 of the outer member are merged,the narrow annular orifice 40' being formed between a conical surf-ace124 of the outer member 120 and a conical surface 125 of the innermember 121. The resulting high-velocity jet is still directed forwardlyalong the mixing chamber 33 albeit in a direction which slightlyconverges. This is often advantageous inasmuch as the fluid medium thentraverses the forward edges of the segments of the vibratory member in adirection slightly angled relative to the longitudinal dimension of suchsegments and produces shear effects. In addition, the width of theannular orifice 40 can be very accurately controlled by the actuatorpreviously described with reference to FIG. 1.

If the gaseous medium is a permanent gas such as air, nitrogen, carbondioxide, etc. its presence in the mixed product can serveto aerate thelatter. This action is often desirable as in the production of emulsionsof high fat content. For example the invention can be used to emulsifyvegetable oils or liquid animal fats with nitrogen alone or combinedwith CO CO or other gases. If however the gaseous medium is saturated orsuperheated steam and if the liquid stream is at a lower temperature,the steam not only induces the vibration but condenses in situ in theliquid to heat same and form extremely small droplets of water whichremain as a part of the mixed product as it is withdrawn, beingstabilized either by their extremely small size or by the presence ofemulsifying agents. This type of action is particularly desirable in theproduction of whipped toppings, etc. For example the invention can beemployed to produce a Whipped cream substitute by using steam attemperatures of about 300-380 F. in apparatus similar to FIG. 8 toemulsify a mixture of vegetable protein, vegetable and/or nut oils andan emulsifying agent such as soy lecithin, plus flavoring and/orsweetening materials.

The mixing apparatus thus far described in detail can be used tocontinuously mix the ingredients of a liquid stream. In some instances,however, it is desirable to employ the invention in a recirculationsystem whereby a batch of the material can be processed by repeatedpassage through the mixing chamber. In FIG. 1 the exit conduit 25 isshown as connected to a spray device in the upper interior of acollection vessel 150. The mixed product is sprayed and additionallymixed in this way and in passing through a pump 151 shown as disposed ina conduit 152 connected to the inlet passage 72. The pump 151 canalternatively be positioned in the exit conduit 25 or another pump canbe therein positioned to facilitate the recirculation. There can be somedegree of aeration in the collection vessel 150. In addition, the liquidstream passing through the vibration zone of the mixing chamber 33 canbe further aerated by a gaseous medium used to induce the vibration orfurther hydrated by the condensate particles previously mentioned.

As an example of the invention when employed in the manufacture of creamsubstitutes, an apparatus as shown approximately full size in FIG. 2.was used under the following conditions. A mixture of a vegetable or nutoil (about 4-30 water (about 60-65 sugar (about 7%) and a fraction of apercent of an emulsifying agent selected from the class of mono-, diandtri-glycerides was circulated through the system of FIG. 1 for a periodof five minutes, employing steam at a temperature of about 360 F. as thegaseous medium for effecting vibration of the segments of the vibratorymember 6%). The resulting product had a particle size averaging 10microns or less and compared with a product produced-by circulating thesame mixture through the same equipment for 45 minutes in the absence ofthe invention in the recirculation line.

Various changes and modifications can be made without departing from thespirit of the invention as defined in the appended claims.

I claim as my invention:

1. A mixing apparatus comprising: a housing including a chamber with aninner wall; a nozzle including concentric members providing a narrowannular orifice therebetween spaced from said wall and discharging intosaid chamber in a given direction; means for delivering to said nozzle ahigh-pressure gaseous medium discharging from said orifice in saiddirection as a high-velocity jet; a tubular cylindrical vibratory memberfacing in a direction substantially opposite to said given direction andhaving a forward edge facing but spaced from said annular orifice, saidforward edge and said annular orifice being in axial alignment, saidforward edge being positioned to be contacted by said annular stream tobe vibrated thereby; and means for circulating a stream of liquidmaterial into and from said chamber through said vibratory member to bemixed by the vibrations thereof.

2. A mixing apparatus as defined in claim 1 in which said nozzlecomprises an outer member having a conical surface and a substantiallycylindrical surface extending from said conical surface toward saidforward edge of said vibratory member, and an inner member movablerelative to the outer member and having a mating conical surface and asubstantially cylindrical surface extending from said conical surfacetoward said forward edge of said vibratory member, said substantiallycylindrical surfaces being spaced to define said narrow annular orificetherebetween.

3. A mixing apparatus as defined in claim 1 in which said tubularvibratory member contains a plurality of peripherally-spaced slotsextending from said forward edge substantially parallel to the axis ofsuch tubular member and dividing the forward portion of such member intoat least two reed-like cylindrical segments separated by said slots andcapable of independent vibration, each of said reed-like segments havingan end facing said narrow annular orifice.

4. A mixing apparatus comprising: a tubular housing; an outer annularmember dividing the interior of said tubular housing into a mixingchamber and an inlet chamber; an inner annular member within said outermember and cooperating therewith in defining a narrow annular orificeinterconnecting said inlet and mixing chambers; means for delivering agaseous medium under pressure to said inlet chamber, said orificeproducing a high-velocity annular stream directed into said mixingchamber in the direction of the axis of said tubular housing; a basemember in said tubular housing at a position downstream from saidorifice; a tubular vibratory member having a rear portion with an innersurface positioned by said base member and a forward portion terminatingin a forward edge positioned in the path of said annular stream to bevibrated thereby; conduit means for delivering a liquid stream to saidmixing chamber to flow past said forward portion, the vibrations thereofintermixing the components of said liquid stream and mixing same withsaid gaseous medium to produce a mixed product; and exit means forwithdrawing at least a portion of said mixed product from said mixingchamber from a position Within said rear portion of said tubularvibratory member adjacent the inner surface of said rear portion.

5. A mixing apparatus comprising: a tubular housing providing a chamberwith an inner wall and containing an inlet end and a discharge end; anozzle at the inlet end including concentric spaced members providing anarrow annular orifice therebetween spaced from said inner wall anddischarging into said chamber; a sleeve member with a forward endpositioned in the chamber adjacent the discharge end and including anouter Wall in sealing engagefrom the inner wall of the chamber; meansfor delivering a high-pressure gaseous medium to said nozzle fordischarge into said chamber through the orifice to vibrate thecylindrical vibratory member; means for introducing a liquid materialinto the chamber between the orifice and the vibratory member to bemixed by the vibrations of the latter; and passage means between theinterior of the sleeve and the discharge end of the chamber forwithdrawing the result product.

6. A method of mixing the components of a liquid stream and a gaseousstream by the use of a vibratory member terminating in an edge, whichincludes the steps of: forming the gaseous stream into a high velocityjet directed toward said edge to vibrate the same at ultrasonicfrequency; delivering the liquid stream to the zone of such vibrationand employing the vibration to aid in mixing the components of saidliquid and gaseous streams 8 to produce a mixed product, said gaseousstream comprising steam and the liquid stream being at a temperaturelower than said steam to condense the same into minute particles forminga part of said mixed product, the condensing of the steam heating theliquid stream and aiding the mixing by increasing the cavitation effectproduced by the ultrasonic vibrations; and withdrawing such mixedproduct continuously from the zone of said vibration.

7. A method of mixing the components of a liquid stream and a gaseousstream utilizing a vibrating member which terminates in an edge,including the steps of: directing the gaseous stream as a high velocityjet toward said edge to vibrate the same; delivering the liquid streamto the zone of such vibration and employing the vibration ous streams toform a product, incoming liquid stream being lower than the vaporizationtemperature of the gaseous stream to cause the latter to condense insaid zone of vibration in a percussive collapse which further aids inthe mixing of said components; and withdrawing such product from thezone of vibration.

8. In a method of mixing together the components of a liquid stream anda gaseous stream utilizing a vibrating member, the step of deliveringthe liquid stream to the zone of vibration at a temperature lower thanthe vaporization temperature of the gaseous stream to reduce thetemperature of the latter and cause it to condense with a percussivecollapse and thereby aid in the mixing of said components.

9. In a method of mixing together the components of a liquid stream anda stream of high pressure steam utilizing a vibrating member, the stepof delivering the liquid stream to the zone of vibration at atemperature lower than the vaporization temperature of water to reducethe temperature of the steam and cause it to condense with a percussivecollapse and thereby aid in the mixing of said components.

References Cited in the file of this patent UNITED STATES PATENTS UNITEDSTATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,081,979March 19, 1963 Ernest E. Lindsey It is hereby certified that errorappears in the above numbered patent requiring correction and that thesaid Letters Patent should read as corrected below.

Column 7, line 28, for "and containing" read said chamber having lines32 and 33 strike t, "with a forward end"; line 34, for "and including"read said sleeve member having a forward end and having line 46, for"result" read resulting Signed and sealed this 15th day of October 1963.

(SEAL) Attest:

EDWIN L. REYNOLDS ERNEST W SWIDER Attesting Officer Ac ting Commissionerof Patents

1. A MIXING APPARATUS COMPRISING: A HOUSING INCLUDING A CHAMBER WITH ANINNER WALL; A NOZZLE INCLUDING CONCENTRIC MEMBERS PROVIDING A NARROWANNULAR ORIFICE THEREBETWEEN SPACED FROM SAID WALL AND DISCHARGING INTOSAID CHAMBER IN A GIVEN DIRECTION; MEANS FOR DELIVERING TO SAID NOZZLE AHIGH-PRESSURE GASEOUS MEDIUM DISCHARGING FROM SAID ORIFICE IN SAIDDIRECTION AS A HIGH-VELOCITY JET; A TUBULAR CYLINDRICAL VIBRATORY MEMBERFACING IN A DIRECTION SUBSTANTIALLY OPPOSITE TO SAID GIVEN DIRECTION ANDHAVING A FORWARD EDGE FACING BUT SPACED FROM SAID ANNULAR ORIFICE, SAIDFORWARD EDGE AND SAID ANNULAR ORIFICE BEING IN AXIAL ALIGNMENT, SAIDFORWARD EDGE BEING POSITIONED TO BE CONTACTED BY SAID ANNULAR STREAM TOBE VIBRATED THEREBY; AND MEANS FOR CIRCULATING A STREAM OF LIQUIDMATERIAL INTO AND FROM SAID CHAMBER THROUGH SAID VIBRATORY MEMBER TO BEMIXED BY THE VIBRATIONS THEREOF.